For the proposed Phase I research, we plan to apply a newly designed subtraction strategy to remove repetitive sequences from microdissected DNA, and to generate new repetitive sequence-deplete libraries for microdissected arm probes. fluorescence in situ hybridization (FISH) technique developed in 198015 revolutionized cytogenetics study. Application of human whole chromosome painting probes, chromosome arm painting probes and chromosome band-specific painting probes in single and multi-color FISH, spectrum karyotyping and interphase FISH has greatly facilitated chromosome abnormality studies in both cancer and hereditary disease research. Our new method will simplify the protocol for research scientists using DNA probes in FISH. it will meet the demands of advanced FISH techniques. During Phase I, we will generate repetitive sequence-deplete DNA painting probes and libraries for chromosome arms 5p, 9q, 12p and 15q and chromosome terminal bands 12qter and 18qter. During Phase II, we will generate repetitive sequence-deplete DNA painting probes and library for all human chromosomes, arms and terminal bands. PROPOSED COMMERCIAL APPLICATIONS: Our new method will greatly reduce the costs of DNA probes production. It will simplify protocol for FISH, thus saving time and labor for research scientist, and yet meets the demand of advanced techniques. The DNA probes generated by this new method will be utilized world wide.